A Weighty Subject

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After a two year break the parity debate has reared its ugly head again. Last time it was over the FG-X Falcon's alleged aerodynamic advantage This time it concerns the weight, or rather weight distribution of the new ZB Commodore.

The ZB is the first ever imported Commodore, and that in itself has changed the way Triple 8 operates. Traditionally, Supercars teams have constructed cars using production bonnets, roofs and bootlids. The remaining panels are all carbon-composite replicas. Opel’s recent ownership change made it harder for Triple 8 to source panels for the ZB, so for the first time in Supercars, they had to run an all-composite body. As Triple 8 owner Roland Dane explained, “we couldn’t get roofs out of Germany so we had to do a car with a composite roof.”

Supercars requires certain parts of the car, the bonnet, boot lid and lights, to be taken straight from the road car, but they have on multiple occasions allowed exceptions where factory parts have been too expensive or hard to find. The LED lights on the Erebus E63 AMG and FG-X Falcon are examples of this. Another example is the ZB Commodore’s bonnet roof and tailgate.

Triple 8 team manager Mark Dutton argues that the weight savings offered by the composite roof is offset by other Commodore-specific parts. The Commodore is a hatch and not a sedan like the Falcon and Altima affects the way that the rear of the car is constructed. The Commodore has heavy roof-mounted boot hinges that the others don't have. Supercars technical regulations mandate that the fuel cell is separated from the cabin by the rear firewall. The Falcon and Altima use steel firewalls from their respective road cars. ZB road car doesn’t have a firewall. To comply with the fuel cell rules, Triple 8 has designed their own carbon-composite firewall and an internal second rear window that no other Supercar has had. Nowhere in the rule book does it say that a steel firewall is mandatory.

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Dutton doesn't believe they have an advantage at all. “What the other teams are saying about the car roof compared to their steel roof, but we’ve got a hatch, with hinges on the roof, we’ve got all that weight higher, and we’ve got two rear windscreens where they’ve only got one. There’s all these little bits and pieces and Supercars, I believe, did the right thing, added all those weights up, worked out the weights, worked out the centre of gravity, and said, ‘you know what? Actually, you’re all pretty much the same”.

If the ZB really is better, and does go on to win the championship it would be nothing new. Every Falcon and Commodore since the VT, excluding the AU Falcon, won the championship in its first season. It doesn't often take long to adapt to the new car either. In 2007, the first eight races were won with new VE Commodores. FG Falcon drivers won the first six races of 2009.

 The VE Commodore was dominant in its first season

The VE Commodore was dominant in its first season

Advantage or not, Triple 8 has done nothing wrong. Nissan Motorsport co-owner Todd Kelly argues that it's unfair to expect Ford and Nissan teams to pay to re-homologate their cars to catch up to the Holden teams, but that's the way it is. Having already allowed the ZB to be homologated with composite panels, Supercars can't now force them to switch to steel. Ford and Nissan teams are, however, allowed to homologate their own composite panels, providing they offer no performance advantage.

That may prove a sticking point. Currently, as Mark Larkham pointed out, the Holden teams aren't enjoying a performance advantage. Last weekend we saw the usual suspects performing well. All three manufacturers qualified in the top 10. There were no surprises in who finished where in either race. Van Gisbergen won both races again. Courtney finished on the podium like he often does at Adelaide. McLaughlin was third on Saturday. On Sunday, Chaz Mostert was matching the lap times of the three front-running Commodores with his Tickford Falcon. As it stands there is no unfair advantage for Holden, so Supercars doesn't have anything to act on.

Running as competitively as they are, it would be difficult for Ford and Nissan teams to re-homologate any parts. On the other hand, it's easy to see how switching to composite panels would offer a performance advantage. For all we know, Dutton is correct and the composite roof is offset by the Extra rear window and roof-mounted hatch hinges. From here it will get messy. If Ford and Nissan teams are permitted to run composite roofs and bonnets, Holden will seek to have them run ballast under the rear section of the roof to compensate for the boot hinges and rear windows. Ford and Nissan teams will then demand Holden teams have ballast equivalent to Falcon and Altima hinges. Before acting on anything, We won't really know if the Falcon and Altima are at a disadvantage until we get to a higher speed track like Phillip Island, where a lower centre of gravity would have a more profound effect.

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Supercars is planning to monitor the performance of the different cars and teams over the coming rounds before making a decision. If Tickford and Penske start lagging behind Triple 8 and Erebus, they may have a point.

Unlike Kelly, Tickford and DJR Team Penske are understanding of Triple 8’s situation, having been in the same place themselves with rear lights, and aren't interested in pegging back Holden. They want to have the same opportunities. “There’s no doubt that due to some of the supply issues and that they’ve had to go a certain path with that new Commodore and it’s ended up with a long, long list of composite parts on it that we don’t currently have,“ said Tickford manager Tim Edwards in the Adelaide paddock.

Both Tickford and DJR Team Penske are weighing up the idea of re-homologating the Falcon with a composite roof and bonnet. The responsibility to re-homologate it ultimately falls with Tickford, the Ford homologation team, but Penske would contribute to the effort. Edwards has already ruled out changing the firewall, but is open to changing the bonnet and roof.

One way to resolve the issue in a way that keeps the Kellys happy would be to use the same solution adopted for engine CoG parity. The Volvo B8444S engine was considerably smaller and lighter than the Ford SVO Boss 302, Holden Motorsport V8. Nissan VK and Erebus M156. That meant Garry Rogers Motorsport had to run extra ballast, which they placed on the floor. Naturally the other teams protested. New engine CoG rules were introduced and GRM was forced to move its ballast around the engine. A simple, if not entirely accurate way to improve body parity would be to allow the Falcon and Altima to run composite roofs with ballast replicating the Commodore's hinges. The Falcon and Altima’s steel bootlids and Commodore's two rear windows are harder to balance out. Composite boots for all and C pillar ballast for Falcon, Altima and any future sedans?

 The Volvo S60 was the last car to raise CoG parity concerns

The Volvo S60 was the last car to raise CoG parity concerns

If nothing is done, this problem will eventually sort itself out. The Falcon and Altima will be replaced at some point. With the precedent already set, these cars will have all-composite bodies. What those cars are and what parity disputes they will bring is anyone's guess. For now, maybe Supercars should just wait and see.